[35857] in bugtraq
Re: eSafe: Could this be exploited?
daemon@ATHENA.MIT.EDU (Andreas Constantinides (MegaHz))
Mon Jul 26 17:14:39 2004
From: "Andreas Constantinides (MegaHz)" <megahz@megahz.org>
To: 3APA3A <3APA3A@SECURITY.NNOV.RU>
Cc: Hugo van der Kooij <hvdkooij@vanderkooij.org>, bugtraq@securityfocus.com
In-Reply-To: <18610004519.20040724152743@SECURITY.NNOV.RU>
Content-Type: text/plain
Message-Id: <1090765495.6239.2.camel@localhost.localdomain>
Mime-Version: 1.0
Date: Sun, 25 Jul 2004 17:24:55 +0300
Content-Transfer-Encoding: 7bit
which version of eSafe are we talking about? 3 or 4 ?
On Sat, 2004-07-24 at 14:27, 3APA3A wrote:
> Dear Hugo van der Kooij,
>
> --Friday, July 23, 2004, 10:21:22 PM, you wrote to bugtraq@securityfocus.com:
>
> HvdK> Both as NitroEngine or CVP server they will push as much of 80% to the
> HvdK> end-user before they stop a virus. Then they rely on the adding of the
> HvdK> exact URL so that URL can be blocked in all next requests.
>
> It depends on how antiviral check is actually implemented. If connection
> is broken immediately after signature is detected - there is no way to
> download infected file, because signature will not pass to client and
> client will not be able to use "Range:" header to resume partially
> downloaded file.
>
> If antiviral filter checks data _after_ all data received from client
> with 20% buffering yes, it's possible to bypass this check for HTTP,
> because there is no way (at least for HTTP/1.0 and FTP) to indicate
> error to client and make him to delete partially downloaded data.
>
> You can check it, by sending EICAR with some additional data: if you can
> find EICAR signature on the client after connection is broken by
> antiviral filter you can bypass it's protection.
>
